No abstract

A hybrid thermo-reversible crosslinking polyurethane nanocomposite containing 0.5, 1, and 2 wt.% of nano-silica was prepared with three intrinsic self-healing bonds (reversible covalent bonds supported by intrinsic hydrogen bonds and dangling chains). Owing to the introduction of pseudo-tannin and polyester diol that could form phenol-urethane networks and using nano-silica that causes dangling chains and hydrogen bonds, the prepared polyurethanes are capable of being reversed at 110 °C and rejoin at low temperatures. Thermoset self-healing polyurethane nanocomposites are prepared from pseudo-tannin, nano-silica, and a urethane-based prepolymer. The investigations of chemical structure, self-healing behavior, and cross-link network are carried out by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) technique, and swelling test. dissociation of phenolic urethane at 110 °C was confirmed by temperature variable FTIR. By swelling test, it was found that the self-healing polyurethane nanocomposites with 0.5 wt.% of nano-silica have the most hard-domain, gel content, and crosslink density in the samples. DSC technique shows that polyurethane samples have two heat transfer transitions (dangling chains and self-healing). Thermogravimetric analysis (TGA) findings show that nanocomposites decompose at elevated temperatures than neat PU, and the rate of degradation diminishes as silica content increases.